DE102008043475B4 - Device control method and device control device - Google Patents

Abstract

Method for controlling a device (2, 3) using a rotation rate sensor (13), with the following steps: - detection of a first sensor signal (S1) for a first seismic mass (11) of the rotation rate sensor (13); - detection of a second sensor signal (S2) for a second seismic mass (12) of the rotation rate sensor (13), - determining a linear acceleration variable on the basis of the first sensor signal (S1) and the second sensor signal (S2); and- determining a rotation rate variable on the basis of the first sensor signal (S1) and the second sensor signal (S2); and- controlling the device (2, 3) as a function of the linear acceleration variable and the rotation rate variable.

Description

State of the art

The present invention relates to a method for controlling a device according to claim 1 and a device for controlling the device according to claim 4.

Such a method for controlling a device using a rotation rate sensor determines a rotation rate and controls the device depending on the determined rotation rate and an acceleration quantity that is measured by an acceleration sensor. The device is, for example, a safety device such as a front airbag, a side airbag or a roll bar, which protects the occupant (s) of a motor vehicle when it rolls over. To control the device, a trigger signal is determined so that the side airbags are inflated or the roll bar is extended when the motor vehicle overturns. The highest level of reliability is required to trigger this safety device, since the triggering of the safety device itself can cause an accident.

A disadvantage is that all signals, i.e. the rate of rotation rate and the acceleration rate for which triggering is required. If one of the signals were faulty, the safety device could fail. For this reason, the process is monitored with various measures and checked for plausibility. In particular if both signals were faulty, as would be the case for so-called common cause errors, the safety device could be triggered without a rollover. The acceleration sensor and the rotation rate sensor are therefore designed in separate housings, each with an evaluation ASIC, in order to avoid common error paths due to a cause or external fault in both sensors at the same time. This increases the manufacturing costs.

In block letters DE 10 2007 012 163 A1 discloses a rotation rate sensor in which seismic masses are set into vibration, wherein a rotation of the sensor can be detected on the vibrating masses via a Coriolis force caused by the rotation. This sensor can be used to detect one or more rotational accelerations or yaw acceleration. The core idea of this publication is to couple the seismic masses to one another by means of a coupling bar in such a way that a linear disturbance variable, which would lead to a movement of the seismic masses in one direction, is suppressed.

Disclosure of the invention

The present invention has for its object to provide a method for controlling a device and a device for controlling the device, which allow a particularly compact design of the device.

The object on which the invention is based is achieved by a method for controlling a device with the features of the characterizing part of patent claim 1 and a device for controlling a device with the features of the characterizing part of patent claim 4.

The present invention relates to a method for controlling a device using a rotation rate sensor,
using a rotation rate sensor with the following steps: detecting a first sensor signal for a first seismic mass of the rotation rate sensor; Detecting a second sensor signal for a second seismic mass of the rotation rate sensor; Determining a linear acceleration variable on the basis of the first sensor signal and the second sensor signal; Determining a rotation rate variable on the basis of the first sensor signal and the second sensor signal; and controlling the device depending on the linear acceleration quantity and the rotation rate quantity. The linear acceleration variable advantageously makes it possible to use a further measurement variable in addition to the rotation rate variable for controlling the device. The acceleration quantity is a quantity that depends on an acceleration in an area of interest, preferably is proportional to a linear acceleration in a reference system. The use of an acceleration variable and a rotation rate variable has already proven itself in practice as a criterion for determining a trigger signal.

In another preferred embodiment, the method has the following further steps: detecting a further acceleration variable; and controlling the device depending on the further acceleration quantity. The acceleration variable is used as a redundant measurement variable in order to check the correctness of the further measurement variable and thus to increase the reliability of the method.

In a development of the latter preferred embodiment, the device is triggered when the linear acceleration quantity exceeds a threshold value and when the further acceleration quantity exceeds a further threshold value. Such a criterion is particularly easy to implement.

The present invention further relates to a device for controlling a device using a rotation rate sensor which has a first seismic mass and a second seismic mass, the device being set up to determine a linear acceleration quantity on the basis of the first sensor signal and the second sensor signal, a rotation rate quantity to determine on the basis of the first sensor signal and the second sensor signal and to trigger the device as a function of the acceleration variable and the rotation rate variable.

In yet another preferred embodiment, the device is also set up to control the device as a function of a further acceleration variable from an acceleration sensor. The trigger signal and the yet another trigger signal can also be identical if the safety device is only to be triggered by a signal.

In another preferred embodiment, an evaluation device for the rotation rate sensor, an evaluation device for the acceleration sensor and a plausibility check device are designed as an integrated circuit.

In a further development of the last-mentioned preferred embodiment, the device, the acceleration sensor, the rotation rate sensor and the integrated circuit are integrated on one chip. The chip is packaged in a housing. The overall size of the individual elements can be reduced and the manufacturing process can be simplified. This results in cost savings. It is also possible to integrate the evaluation device for the rotation rate sensor and the rotation rate sensor on one chip and / or to integrate the evaluation device for the acceleration sensor and the acceleration sensor on one chip.

Figure list

• 1 eine Vorderansicht eines seitlich geneigten Kraftfahrzeugs;
• 2 eine vereinfachte schematische Ansicht eines Drehratensensors; und
• 3 eine schematische Ansicht der Vorrichtung zum Steuern von Airbags.

The invention is described in more detail below with reference to the drawings. Show it:

• 1 a front view of a laterally inclined motor vehicle;
• 2nd a simplified schematic view of a rotation rate sensor; and
• 3rd a schematic view of the device for controlling airbags.

beschreiben, der entlang der x-Achse eines ortsfesten Koordinatensystems 5 gerichtet ist. Damit die seitlichen Airbags für den Fall eines Überschlags rechtzeitig ausgeblasen sind, um den oder die Fahrzeuginsassen zu schützen, wird ein Betrag einer Drehrate des Kraftfahrzeugs in Grad/s und ein Betrag einer Beschleunigung in y- bzw. z-Richtung als Auslösekriterium verwendet. Zusätzlich kann auch der Drehwinkel herangezogen werden, um den die y-Achse gegenüber einer Horizontalen gedreht ist. Der Drehwinkel kann durch Integration des Winkelgeschwindigkeitsvektors $\overrightarrow{\omega }$

berechnet werden. 1 shows a front view of a laterally inclined motor vehicle 1 . The car 1 has two side airbags in the passenger compartment 2nd and 3rd on. A device 4th for controlling airbags 2nd , 3rd first of all checks what the driving situation is, ie whether, for example, the motor vehicle 1 will exceed a critical sideways slope and will most likely roll over and, depending on this, cause the airbags to deploy 2nd , 3rd . The side airbags 2nd and 3rd and the device 4th to control the airbags 2nd , 3rd are through the body of the motor vehicle 1 hidden and therefore drawn in dashed lines to indicate their positions. A rotation of the motor vehicle 5 that leads to the lateral inclination is indicated by an angular velocity vector $\overrightarrow{\omega }$

describe the along the x-axis of a fixed coordinate system 5 is directed. So that the side airbags are blown out in time in the event of a rollover in order to protect the vehicle occupant (s), an amount of a rotation rate of the motor vehicle in degrees / s and an amount of acceleration in the y or z direction are used as the triggering criterion. In addition, the angle of rotation by which the y-axis is rotated relative to a horizontal can also be used. The angle of rotation can be achieved by integrating the angular velocity vector $\overrightarrow{\omega }$

be calculated.

Die zweite seismische Masse 7 schwingt dann mit der Geschwindigkeit ${\overrightarrow{v}}_2={\overrightarrow{v}}_0\cdot \text{sin}\left(\mathrm{\Omega }\cdot t+\mathrm{\pi }\right)=-{\overrightarrow{v}}_0\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)$

Die Achsen x', y' und z' fallen jeweils mit den Achsen x, y und z zusammen, wenn das Kraftfahrzeug 1 nicht geneigt ist. Unter der ersten seismischen Masse 6 ist eine erste Elektrode 11 auf dem Substrat vorgesehen. Unter der zweiten seismischen Masse 7 ist eine zweite Elektrode 12 auf dem Substrat vorgesehen. Die beiden seismischen Massen 6, 7 sind jeweils elektrisch von den Elektroden isoliert. Wenn sich der Drehratensensor 13 mit dem Koordinatensystem 5 und die x-Achse dreht, wirkt in dem Koordinatensystem x', y' und z' auf die erste seismische Masse 6 in dem Koordinatensystem 10 mit den Achsen x', y' und z' eine erste Corioliskraft ${\overrightarrow{F}}_c=2m\cdot \left({\overrightarrow{v}}_1\times \overrightarrow{\omega }\right)=2m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)$

und auf die zweite seismische Masse 7 in dem Koordinatensystem x', y', z' eine zweite Corioliskraft ${\overrightarrow{F}}_c=2m\cdot \left({\overrightarrow{v}}_2\times \overrightarrow{\omega }\right)=-2m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right).$

Zusätzlich können auf jeder der seismischen Massen 6, 7 eine lineare identische Beschleunigungskraft ${\overrightarrow{F}}_{lm}$

wirken. An der ersten Elektrode 11 wird ein erstes Signals S1 erzeugt, welches proportional zu einer ersten Kraft ${\overrightarrow{F}}_c=2m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)+{\overrightarrow{F}}_z$

ist. An der zweiten Elektrode 12 wird ein zweites Signals S2 erzeugt, welches proportional zu einer zweiten Kraft ${\overrightarrow{F}}_c=2m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)+{\overrightarrow{F}}_z$

ist. Durch Addition des ersten Signals S1 und des zweiten Signals S2 ergibt sich eine Beschleunigungsgröße $S_{acc}\propto {\overleftarrow{F}}_1+{\overleftarrow{F}}_1=2{\overleftarrow{F}}_z$

welches proportional zu einer Beschleunigung in z'-Richtung ist. Durch Subtraktion des ersten Signals S1 von dem zweiten Signal S2 ergibt sich eine Drehratengröße $S_{rot}\propto 4m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)$

welches proportional zur Drehung um die x-Achse ist. Aus dem Stand der Technik sind Drehratensensoren mit unterschiedlichem Aufbau bekannt. Dementsprechend können auch Beschleunigungsgrößen bestimmt werden, die in jeder beliebigen Richtung gerichtet sind. 2nd shows a simplified schematic view of a rotation rate sensor 13 . The rotation rate sensor 13 is symmetrical and comprises a first seismic mass 6 with mass m1 and a second seismic mass 7 with the mass m2, both of which are equally heavy due to the symmetry (m = m1 = m2). The seismic masses 6 , 7 are about a spring 8th coupled to one another and connected directly to a substrate underneath via further springs (not shown) or indirectly via further springs and further elements. The seismic masses 6 , 7 have a certain electrical potential. Drive devices 9 displace the seismic masses 6 , 7 using an AC voltage along the y'-axis of a coordinate system 10th , which can be found together with the rotation rate sensor 13 moved, in opposite vibrations with the frequency Ω. The first seismic mass 6 then vibrates at speed ${\overrightarrow{v}}_1={\overrightarrow{v}}_0\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right).$

The second seismic mass 7 then vibrates at speed ${\overrightarrow{v}}_{\mathrm{2nd}}={\overrightarrow{v}}_0\cdot \text{sin}\left(\mathrm{\Omega }\cdot t+\mathrm{\pi }\right)=-{\overrightarrow{v}}_0\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)$

The axes x ', y' and z 'coincide with the axes x, y and z when the motor vehicle 1 is not inclined. Under the first seismic mass 6 is a first electrode 11 provided on the substrate. Below the second seismic mass 7 is a second electrode 12 provided on the substrate. The two seismic masses 6 , 7 are electrically isolated from the electrodes. If the rotation rate sensor 13 with the coordinate system 5 and the x-axis rotates, acts on the first seismic mass in the coordinate system x ', y' and z ' 6 in the coordinate system 10th with the axes x ', y' and z 'a first Coriolis force ${\overrightarrow{F}}_c=\mathrm{2nd}m\cdot \left({\overrightarrow{v}}_1\times \overrightarrow{\omega }\right)=\mathrm{2nd}m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)$

and on the second seismic mass 7 a second Coriolis force in the coordinate system x ', y', z ' ${\overrightarrow{F}}_c=\mathrm{2nd}m\cdot \left({\overrightarrow{v}}_{\mathrm{2nd}}\times \overrightarrow{\omega }\right)=-\mathrm{2nd}m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right).$

Additionally, each of the seismic masses can 6 , 7 a linear identical acceleration force ${\overrightarrow{F}}_{lm}$

Act. On the first electrode 11 becomes a first signal S1 generated which is proportional to a first force ${\overrightarrow{F}}_c=\mathrm{2nd}m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)+{\overrightarrow{F}}_{\mathrm{e.g.}}$

is. On the second electrode 12 becomes a second signal S2 generates which is proportional to a second force ${\overrightarrow{F}}_c=\mathrm{2nd}m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)+{\overrightarrow{F}}_{\mathrm{e.g.}}$

is. By adding the first signal S1 and the second signal S2 an acceleration quantity results $S_{acc}\propto {\overleftarrow{F}}_1+{\overleftarrow{F}}_1=\mathrm{2nd}{\overleftarrow{F}}_{\mathrm{e.g.}}$

which is proportional to an acceleration in the z 'direction. By subtracting the first signal S1 from the second signal S2 there is a rate of rotation rate $S_{rOt}\propto \mathrm{4th}m\cdot \left({\overrightarrow{v}}_0\times \overrightarrow{\omega }\right)\cdot \text{sin}\left(\mathrm{\Omega }\cdot t\right)$

which is proportional to the rotation around the x-axis. Rotation rate sensors with different designs are known from the prior art. Acceleration quantities directed in any direction can also be determined accordingly.

3rd shows a schematic view of the device 4th for controlling airbags 2nd , 3rd . The device comprises the rotation rate sensor 13 , the accelerometer 14 and the integrated circuit 15 . The two signals S1 and S2 of the rotation rate sensor 13 and a signal S3 of the acceleration sensor 14 become the integrated circuit 15 fed. The integrated circuit 15 is an ASIC, which is a circuit for evaluating the two signals S1 and S2 of the rotation rate sensor 13 , a circuit for evaluating the signal S3 of the acceleration sensor 14 and comprises a plausibility check device. The circuit for evaluating the two signals S1 and S2 of the rotation rate sensor 13 determined from the signals S1 and S2 an acceleration quantity Sacc, which is proportional to an acceleration in the z ′ direction, and a rotation rate quantity Srot. The signal S3 can according to the structure of the acceleration sensor 14 be dependent on an acceleration in the x ', y' and / or z 'direction. The circuit for evaluating the signal S3 of the acceleration sensor 14 determined from the signal S3 an acceleration variable in the x ', y' and / or z 'direction. The plausibility check device now checks whether the determined rotation rate and acceleration quantities are plausible, ie clearly indicate a specific driving situation such as a rollover of the motor vehicle or not.

• i.) die Beträge der Drehrate um eine Drehachse in x'-Richtung und der Beschleunigung in y'-Richtung überschreiten jeweils einen bestimmten Wert für eine gewisse Zeitdauer;
• ii.) die Beträge der Drehrate um eine Drehachse in x'-Richtung und der Beschleunigung in z'-Richtung überschreiten jeweils einen bestimmten Wert für eine gewisse Zeitdauer;
• iii.) die Beträge der Drehrate um eine Drehachse in x'-Richtung und der Beschleunigung in y'-Richtung überschreiten jeweils einen bestimmten Wert für einen bestimmten Neigungswinkel a; oder
• iv.) die Beträge der Drehrate um eine Drehachse in x'-Richtung und der Beschleunigung in z'-Richtung überschreiten jeweils einen bestimmten Wert für einen bestimmten Neigungswinkel a.

The device 15 then outputs a driving situation signal SOUT to the trip device controls 18th , 19th out. The driving situation signal SOUT indicates that a specific driving situation is present. The following criteria are used to determine whether the motor vehicle is rolling over:

• i.) the amounts of the rotation rate about an axis of rotation in the x'-direction and the acceleration in the y'-direction each exceed a certain value for a certain period of time;
• ii.) the amounts of the rotation rate about an axis of rotation in the x'-direction and the acceleration in the z'-direction each exceed a certain value for a certain period of time;
• iii.) the amounts of the rotation rate about an axis of rotation in the x 'direction and the acceleration in the y' direction each exceed a certain value for a certain angle of inclination a; or
• iv.) the amounts of the rotation rate about an axis of rotation in the x'-direction and the acceleration in the z'-direction each exceed a certain value for a certain angle of inclination a.

The amounts of acceleration in the z 'direction can be determined as a linear combination of the two acceleration values in the z' direction. Alternatively, criteria ii.) And iv.) Can be modified such that the amount of the acceleration value, which was determined with the aid of the rotation rate sensor, and the amount of the acceleration value, which was determined with the aid of the acceleration sensor, must each exceed a certain value. For known rotation rate sensors that are constructed or oriented differently, the accelerations in the y ′ direction can also be determined as a linear combination of the acceleration in the y ′ direction or the modified criteria can be applied. The triggering device controls control depending on the current driving situation 18th , 19th finally the triggering devices 16 and 17th so that the side airbags 2nd , 3rd are triggered for a high rollover probability, causing the side airbags to inflate 2nd , 3rd leads. The trip device controls 18th , 19th and the trip devices 16 and 17th are integrated in the side airbags 2,3.

Claims (7)

Method for controlling a device (2, 3) using a rotation rate sensor (13), with the following steps: Detecting a first sensor signal (S1) for a first seismic mass (11) of the rotation rate sensor (13); - Detection of a second sensor signal (S2) for a second seismic mass (12) of the rotation rate sensor (13); - Determining a linear acceleration variable on the basis of the first sensor signal (S1) and the second sensor signal (S2); and - determining a rotation rate variable on the basis of the first sensor signal (S1) and the second sensor signal (S2); and - controlling the device (2, 3) as a function of the linear acceleration variable and the rotation rate variable. Procedure according to Claim 1 , with the following further steps: - detection of a further acceleration variable (S3); and - controlling the device (2, 3) as a function of the further acceleration variable (S3). Procedure according to Claim 2 The device (2, 3) is triggered when the linear acceleration quantity exceeds a threshold value and when the further acceleration quantity (S3) exceeds a further threshold value. Device for controlling a device (2, 3) using a rotation rate sensor (13), the device being set up a linear acceleration variable on the basis of a first sensor signal (S1) for a first seismic mass (11) of the rotation rate sensor (13) and one to determine the second sensor signal (S2) for a second seismic mass (12) of the yaw rate sensor (13), to calculate a yaw rate variable from the first sensor signal (S1) and the second sensor signal (S2) and the device (2, 3) as a function of to control the linear acceleration variable and the rotation rate variable. Device after Claim 4 The device is also set up to generate the device (2, 3) as a function of a further acceleration variable. Device according to one of the Claims 4 or 5 , wherein an evaluation device for the rotation rate sensor (13), an evaluation device for the acceleration sensor (14) and a plausibility check device is designed as an integrated circuit. Device after Claim 6 depending on Claim 5 , wherein the device, the acceleration sensor, the rotation rate sensor (13) and the integrated circuit are integrated on one chip.

Images